Molecular characterization and expression analysis of dihydroflavonol 4-reductase (DFR) gene in Saussurea medusa

• Published in: Molecular biology reports 2012-03, Vol.39 (3), p.2991-2999
• Main Authors: Li, Houhua, Qiu, Jian, Chen, Fudong, Lv, Xiaofen, Fu, Chunxiang, Zhao, Dexiu, Hua, Xuejun, Zhao, Qiao
• Format: Article
• Language: English
• Subjects: Alcohol Oxidoreductases - chemistry; Alcohol Oxidoreductases - genetics; Alcohol Oxidoreductases - metabolism; Animal Anatomy; Animal Biochemistry; Base Sequence; Biomedical and Life Sciences; Callus; Catalysis; Chromatography, High Pressure Liquid; Computational Biology; Deoxyribonucleic acid; DFR gene; DNA; DNA Primers - genetics; DNA, Complementary - genetics; Endangered Species; Enzymes; Escherichia coli; Flavonoids; Flavonoids - metabolism; Flavonols - metabolism; Flowers; Flowers & plants; Flowers - metabolism; Gene expression; Gene Expression Profiling; Histology; Leaves; Life Sciences; Mass Spectrometry; Medicinal plants; Molecular biology; Molecular Sequence Data; Molecular Structure; Morphology; Nutrition; Phylogeny; Polymerase chain reaction; proanthocyanidins; Quercetin - analogs & derivatives; Quercetin - metabolism; Real-Time Polymerase Chain Reaction; Roots; Saccharomyces cerevisiae; Saussurea; Saussurea - enzymology; Sequence Analysis, DNA
• ISSN: 0301-4851; 1573-4978
• DOI: 10.1007/s11033-011-1061-2

Dihydroflavonol 4-reductase (DFR), which catalyzes the reduction of dihydroflavonols to leucoanthocyanins, is a key enzyme in the biosynthesis of anthocyanidins, proanthocyanidins, and other flavonoids of importance in plant development and human nutrition. This study isolated a full length cDNA encoding DFR, designated as SmDFR (GenBank Accession No. EF600682), by screening a cDNA library from a red callus line of Saussurea medusa , which is an endangered, traditional Chinese medicinal plant with high pharmacological value. SmDFR was functionally expressed in yeast ( Saccharomyces cerevisiae ) to confirm that SmDFR can readily reduce dihydroquercetin (DHQ) and dihydrokampferol (DHK), but it could not reduce dihydromyricetin (DHM). The deduced SmDFR structure shared extensive sequence similarity with previously characterized plant DFRs and phylogenetic analysis showed that it belonged to the plant DFR super-family. SmDFR also possessed flavanone 4-reductase (FNR) activity and can catalyze the conversion of eridictyol to luteoforol. Real-time PCR analysis showed that the expression level of SmDFR was higher in flowers compared with both leaves and roots. This work greatly enhances our knowledge of flavonoid biosynthesis in S. medusa and marks a major advance that could facilitate future genetic modification of S. medusa .